One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,6)(3,5,7,8)(9,10)(11,14)(12,16)(13,15)(18,20)(19,23)(25,26,30,27)(28,33,36,31)(29,34,37,32)(35,39,38,40)(9,11,13,16)(10,14,15,12)(19,23)(22,24)(26,27)(29,37)(31,33)(35,38)(9,11)(10,12)(13,16)(14,15)(17,18,21,20)(19,22,23,24)(25,27,30,26)(28,31,36,33)(29,34,37,32)(35,39,38,40)(1,2)(3,5)(4,6)(7,8)(9,11)(10,12)(13,16)(14,15)(17,19,21,23)(18,22,20,24)(25,28,30,36)(26,31,27,33)(29,38,37,35)(32,40,34,39)(1,3,4,7)(2,5,6,8)(9,12)(10,11)(13,14)(15,16)(17,20,21,18)(19,24,23,22)(25,29,30,37)(26,32,27,34)(28,35,36,38)(31,39,33,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.